Slack in Trim Tab

[avenger1949]

Got my Tcraft annual done on sunday and it passed with flying colors which is always good, only concern was the trim tab on the elevator which had a bit more slack then the inspector liked but not excessive. After doing some research on the matter it seems there are some small bushing in there that might need replaced. Is this correct and where might I find them? Would appear covering might have to be removed to get to them or is there an easier way?

Thanks
Bill

[M Towsley]

Re: Slack in Trim Tab

Hi bill,

Both of my bc12's have had some movement in them. There is a lot of little linkage in there you can see from the bottom inspection hole. Never has had any flight issues. More knowledgeable people may have a say but seems to be more trouble than it is worth. How much trailing edge movement is there?

[avenger1949]

Re: Slack in Trim Tab

Hi bill,

Both of my bc12's have had some movement in them. There is a lot of little linkage in there you can see from the bottom inspection hole. Never has had any flight issues. More knowledgeable people may have a say but seems to be more trouble than it is worth. How much trailing edge movement is there?

about a half inch or a tiny bit more since my post I have talked to the 2 other tcraft guys in Wichita and they say they have about the same amount and hadn't thought about it as being bad. Did a google search for taylorcraft trim tabs and found there are some bushing in the yoke said they were available at hobby shops and some hardware stores... I think unless someone thinks this is a major problem will probably leave it as it is.

[Carrieve]

Re: Slack in Trim Tab

I have had some slack in mine for years. My IA, who knows Tcrafts, says it is ok. Mine is about 1/2 at the edge. I still have very accurate trim control when flying so I don't think it is a major problem. I move the handle VERY little and the pitch responds.

[KewFlyer]

Re: Slack in Trim Tab

I also have a small amount of slack in the trim cables. I keep the tail mechanism well greased. My IA takes a look at the tension on those cables at every annual.

[Laz]

Re: Slack in Trim Tab

having just completely rebuilt my BC12-D trim system, with almost all new factory parts (managed to buy them before Harry's operation went Down completely) there will Always be some play in the system. If you take it all out it would probably not work at all.

Laz

[avenger1949]

Re: Slack in Trim Tab

having just completely rebuilt my BC12-D trim system, with almost all new factory parts (managed to buy them before Harry's operation went Down completely) there will Always be some play in the system. If you take it all out it would probably not work at all.

Laz

Thanks guys will take a close look at it but feel it is probably is just the way they are then.
Will check the pins and see if they are worn any and then just keep an eye on it.

Bill Bailey
Wichita Ks

[flyguy]

Re: Slack in Trim Tab

I have some external play and some internal with mine. I have been putting off fixing the external for any number of reasons, all bad. I think it would be pretty good if I fixed the external looseness. Glad y'all reminded me.

One thing to be sure about, any substitution of a non-factory trim tab, say like one made of light plywood, can create a real problem with flutter. My first 12D had a bunch of deadly problems and that was one of them. My buddy caught sight of the tail fluttering while we were flying formation. Needless to say I brought it down very gently and put on the proper factory part.

DC

[Hank Jarrett]

Re: Slack in Trim Tab

Check carefully which tab IS original on yours. Right after the war a lot of planes got original plywood tabs. I have seen several 45s and early 46s with wood tabs, all with exactly the same hardware and hinges. You can't even mount an aluminum tab on my elevator. The hinge is a completely different design, and exactly the same as the other planes with wood tabs. You DO need the correct elevator to use the wood tab.
Hank

[avenger1949]

Re: Slack in Trim Tab

Check carefully which tab IS original on yours. Right after the war a lot of planes got original plywood tabs. I have seen several 45s and early 46s with wood tabs, all with exactly the same hardware and hinges. You can't even mount an aluminum tab on my elevator. The hinge is a completely different design, and exactly the same as the other planes with wood tabs. You DO need the correct elevator to use the wood tab.
Hank

Took a very close look at mine this weekend there isn't any play in the cables, all my play seems to be coming from the yokes involved and the turn buckles do appear to have some bushings at the yoke that might be worn but I have no idea where I might find those, appear to be small bushings at the Control horn on the tab as well.

[Hank Jarrett]

Re: Slack in Trim Tab

You aren't talking about the little AN 111 cable bushings are you? They are the ones that are usually inside the cable thimbles the cable wraps around. You can get them from most of the suppliers for about $1.50 each. Look under AN 111-3
Hank

[avenger1949]

Re: Slack in Trim Tab

You aren't talking about the little AN 111 cable bushings are you? They are the ones that are usually inside the cable thimbles the cable wraps around. You can get them from most of the suppliers for about $1.50 each. Look under AN 111-3
Hank

No this is a little spacer shaped like a top hat that went into the horn on the trim tab sort of a bearing and in the yoke holes where the pins pass through.

[Carrieve]

Re: Slack in Trim Tab

Don't forget about the spring in the ceiling that keeps tension on the cable. You don't want too much or too little. I never oil or lube the cable as it will certainly slip. When this does it gently works one direction and then you have full up or full down and only a little neutral. Been there, done that.